These results indicate that the HFD suppressed mRNA expression of pro-inflammatory cytokines/chemokines and proliferation-associated keratin 16 and increased that of anti-inflammatory cytokine TGF-β1 and cell cycle inhibitor CDKN1A in imiquimod-induced dermatitis, and these effects might be related to the suppression of epidermal hyperproliferation, inflammatory infiltration, and severity of dermatitis. This evidence concerns the gene CDKN1A and dermatitis.